A metal target with atomic number Z = 46 is bombarded with a high energy electron beam. The emission of X-rays from the target is analyzed. The ratio r of the wavelengths of the Kα-line and the cut-off is found to be r = 2. If the same electron beam bombards another metal target with Z = 41, the value of r will be
1
2.53
2
1.27
3
2.24
4
1.58
5
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